Light source device and display

ABSTRACT

A light source device includes: a light guide plate having a first internal reflection plane and a second internal reflection plane which face each other; one or more light sources each applying illumination light through a side surface of the light guide plate into an interior thereof; and an optical device disposed to face the light guide plate, and modulating, for each of partial regions thereof, a state of light rays exiting therefrom. One or both of the first and the second internal reflection planes each have scattering regions each allowing the illumination light from the light sources to be scattered and exit from the first internal reflection plane of the light guide plate, and one or both of the first and second internal reflection planes each have total-reflection regions allowing the illumination light from the light sources to be reflected in a manner of total-internal-reflection.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/351,401, entitled “LIGHT SOURCE DEVICE AND DISPLAY,” filed Jan. 17,2012, which claims priority and benefit under 35 U.S.C. §119 of JapanesePatent Application Serial No. 2011-015569, filed in the Japan PatentOffice on Jan. 27, 2011, all of which are hereby incorporated byreference to the maximum extent allowable by law.

BACKGROUND

The present technology relates to a light source device and a displaycapable of achieving stereoscopic vision by a parallax barrier system.

In related art, as one of stereoscopic display systems which are allowedto achieve stereoscopic vision with naked eyes without wearing specialglasses, a parallax barrier system stereoscopic display is known. FIG.14 illustrates a typical configuration example of the parallax barriersystem stereoscopic display. In the stereoscopic display, a parallaxbarrier 101 is disposed to face a front surface of a two-dimensionaldisplay panel 102. In a typical configuration of the parallax barrier101, shielding sections 111 shielding display image light from thetwo-dimensional display panel 102 and stripe-shaped opening sections(slit sections) 112 allowing the display image light to passtherethrough are alternately arranged in a horizontal direction.

An image based on three-dimensional image data is displayed on thetwo-dimensional display panel 102. For example, a plurality of parallaximages including different parallax information, respectively, areprepared as three-dimensional image data, and each of the parallaximages are separated into, for example, a plurality of stripe-shapedseparated images extending in a vertical direction. Then, the separatedimages of the plurality of parallax images are alternately arranged in ahorizontal direction to produce a composite image including a pluralityof stripe-shaped parallax images in one screen, and the composite imageis displayed on the two-dimensional display panel 102. In the case ofthe parallax barrier system, the composite image displayed on thetwo-dimensional display panel 102 is viewed through the parallax barrier101. When the widths of the separated images to be displayed, a slitwidth in the parallax barrier 101, and the like are appropriately set,in the case where a viewer watches the stereoscopic display from apredetermined position and a predetermined direction, light rays fromdifferent parallax images are allowed to enter into left and right eyes10L and 10R of the viewer, respectively, through the slit sections 112.Thus, when the viewer watches the stereoscopic display from apredetermined position and a predetermined direction, a stereoscopicimage is perceived. To achieve stereoscopic vision, it is necessary forthe left and right eyes 10L and 10R to view different parallax images,respectively, so two or more parallax images, that is, an image for lefteye and an image for right eye are necessary. In the case where three ormore parallax images are used, multi-view vision is achievable. Whenmore parallax images are used, stereoscopic vision in response tochanges in viewing position of the viewer is achievable. In other words,motion parallax is obtained.

In the configuration example in FIG. 14, the parallax barrier 101 isdisposed in front of the two-dimensional display panel 102. For example,in the case where a transparent liquid crystal display panel is used,the parallax barrier 101 may be disposed behind the two-dimensionaldisplay panel 102 (refer to FIG. 10 in Japanese Patent No. 3565391 andFIG. 3 in Japanese Unexamined Patent Application Publication No.2007-187823). In this case, when the parallax barrier 101 is disposedbetween the transmissive liquid crystal display panel and a backlight,stereoscopic display is allowed to be performed based on the sameprinciple as that in the configuration example in FIG. 14.

SUMMARY

However, in a parallax barrier system stereoscopic display, an exclusivecomponent for three-dimensional display, i.e., a parallax barrier isnecessary, and there is an issue that the number of components and anarrangement space are larger than those in a display for two-dimensionaldisplay.

It is desirable to provide a light source device and a display whichinclude a smaller number of components than a parallax barrier systemstereoscopic display in related art, and are capable of achieving spacesaving.

According to an embodiment of the technology, there is provided a lightsource device including: a light guide plate having a first internalreflection plane and a second internal reflection plane which face eachother; one or more light sources each applying illumination lightthrough a side surface of the light guide plate into an interiorthereof; and an optical device disposed to face the light guide plate,and modulating, for each of partial regions thereof, a state of lightrays exiting therefrom, in which one or both of the first internalreflection plane and the second internal reflection plane each havescattering regions each allowing the illumination light from the lightsources to be scattered and exit from the first internal reflectionplane of the light guide plate, and one or both of the first and secondinternal reflection planes, which are planes having the scatteringregions, each have total-reflection regions allowing the illuminationlight from the light sources to be reflected in a manner oftotal-internal-reflection.

According to an embodiment of the technology, there is provided adisplay including: a display section displaying an image; and a lightsource device emitting light for image display to the display section,in which the light source device is configured of the light sourcedevice according to the above-described embodiment of the technology.

In the light source device or the display according to the embodiment ofthe technology, in one or both of the first internal reflection planeand the second internal reflection plane in the light guide plate, thetotal-reflection regions allow illumination light from the light sourcesto be reflected in a manner of total-internal-reflection. Therefore, theillumination light having entered the total-reflection regions istotally reflected in the interior of the light guide plate between thefirst internal reflection plane and the second internal reflectionplane. On the other hand, the scattering regions allow the illuminationlight from the light sources to be scattered, and to exit from the firstinternal reflection plane of the light guide plate. Moreover, theoptical device controls a state of a light ray exiting therefrom foreach of partial regions thereof. Therefore, the light guide plate isallowed to have a function as a parallax barrier. In other words, thelight guide plate is allowed to equivalently function as a parallaxbarrier with the scattering regions as opening sections (slit sections)and the total-reflection regions as shielding sections.

In the light source device or the display according to the embodiment ofthe technology, one or both of the first internal reflection plane andthe second internal reflection plane of the light guide plate each havethe total-reflection regions and the scattering regions; therefore, thelight guide plate is allowed to equivalently have a function as aparallax barrier. Thus, compared to a parallax barrier systemstereoscopic display in related art, the number of components is allowedto be reduced, and space saving is achievable. Moreover, the opticaldevice is allowed to control the state of the light ray exitingtherefrom for each of partial regions thereof; therefore, the functionas the parallax barrier is controllable for each of partial regions.Thus, display switching between three-dimensional display andtwo-dimensional display is controllable for each of partial regions.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the technology as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thetechnology.

FIGS. 1A and 1B are sectional views illustrating a configuration exampleof a stereoscopic display according to a first embodiment of thetechnology with states of emission of light rays from a light sourcedevice, where FIG. 1A illustrates a light ray exiting state duringthree-dimensional display, and FIG. 1B illustrates a light ray exitingstate during two-dimensional display.

FIGS. 2A and 2B are a sectional view illustrating a first configurationexample of a light guide plate surface in the stereoscopic displayillustrated in FIGS. 1A and 1B, and a schematic explanatory diagramillustrating reflection and scattering states of light rays on the lightguide plate surface illustrated in FIG. 2A, respectively.

FIGS. 3A and 3B are a sectional view illustrating a second configurationexample of the light guide plate surface in the stereoscopic displayillustrated in FIGS. 1A and 1B, and a schematic explanatory diagramillustrating reflection and scattering states of light rays on the lightguide plate surface illustrated in FIG. 3A, respectively.

FIGS. 4A and 4B are a sectional view illustrating a third configurationexample of the light guide plate surface in the stereoscopic displayillustrated in FIGS. 1A and 1B, and a schematic explanatory diagramillustrating reflection and scattering states of light rays on the lightguide plate surface illustrated in FIG. 4A, respectively.

FIG. 5 is a plot illustrating an example of luminance distributions on asurface of a display section during three-dimensional display andtwo-dimensional display in the stereoscopic display illustrated in FIGS.1A and 1B.

FIGS. 6A and 6B are sectional views illustrating a configuration exampleof a stereoscopic display according to a second embodiment of thetechnology with a state of light rays exiting from a light sourcedevice, where FIG. 6A illustrates a light ray exiting state duringthree-dimensional display, and FIG. 6B illustrates a light ray exitingstate during two-dimensional display.

FIGS. 7A and 7B are sectional views illustrating a configuration exampleof a stereoscopic display according to a third embodiment of thetechnology with a state of light rays exiting from a light sourcedevice, where FIG. 7A illustrates a light ray exiting state duringthree-dimensional display, and FIG. 7B illustrates a light ray exitingstate during two-dimensional display.

FIG. 8 is a sectional view illustrating a configuration example of astereoscopic display according to a fourth embodiment of the technologywith a state of light rays exiting from a light source device in thecase where only a first light source is in an ON (light-on) state.

FIG. 9 is a sectional view illustrating a configuration example of thestereoscopic display illustrated in FIG. 8 with a state of light raysexiting from the light source device in the case where only a secondlight source is in an ON (light-on) state.

FIG. 10 is a sectional view illustrating a configuration example of thestereoscopic display illustrated in FIG. 8 with a state of light raysexiting from the light source device in the case where both of the firstlight source and the second light source are in an ON (light-on) state.

FIGS. 11A and 11B are a sectional view illustrating a firstconfiguration example of a light guide plate surface in the stereoscopicdisplay illustrated in FIG. 8, and a schematic explanatory diagramillustrating scattering and reflection states of light rays on the lightguide plate surface illustrated in FIG. 11A, respectively.

FIGS. 12A and 12B are a sectional view illustrating a secondconfiguration example of the light guide plate surface in thestereoscopic display illustrated in FIG. 8, and a schematic explanatorydiagram illustrating scattering and reflection states of light rays onthe light guide plate surface illustrated in FIG. 12A, respectively.

FIGS. 13A and 13B are a sectional view illustrating a thirdconfiguration example of the light guide plate surface in thestereoscopic display illustrated in FIG. 8, and a schematic explanatorydiagram illustrating scattering and reflection states of light rays onthe light guide plate surface illustrated in FIG. 13A, respectively.

FIG. 14 is a configuration diagram illustrating a typical configurationexample of a parallax barrier system stereoscopic display.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the technology will be described in detailbelow referring to the accompanying drawings.

(First Embodiment)

[Whole Configuration of Stereoscopic Display]

FIGS. 1A and 1B illustrate a configuration example of a stereoscopicdisplay according to a first embodiment of the technology. Thestereoscopic display includes a display section 1 which displays animage, and a light source device which is disposed on a back surface ofthe display section 1 and emits light for image display toward thedisplay section 1. The light source device includes a light source 2, alight guide plate 3, and an electronic paper 4.

The stereoscopic display is allowed to selectively perform switchingbetween a two-dimensional (2D) display mode on an entire screen and athree-dimensional (3D) display mode on the entire screen as necessary.FIGS. 1A and 1B correspond to a configuration in the three-dimensionaldisplay mode and a configuration in the two-dimensional display mode,respectively. FIGS. 1A and 1B schematically illustrate states ofemission of light rays from the light source device in respectivedisplay modes.

The display section 1 is configured with use of a transmissivetwo-dimensional display panel, for example, a transmissive liquidcrystal display panel, and includes a plurality of pixels configured of,for example, R (red) pixels, G (green) pixels and B (blue) pixels, andthe plurality of pixels are arranged in a matrix form. The displaysection 1 displays a two-dimensional image by modulating light from thelight source device from one pixel to another based on image data. Thedisplay section 1 selectively displays one of an image based onthree-dimensional image data and an image based on two-dimensional imagedata as necessary by switching. It is to be noted that thethree-dimensional image data is, for example, data including a pluralityof parallax images corresponding to a plurality of viewing angledirections in three-dimensional display. For example, in the case wherebinocular three-dimensional display is performed, the three-dimensionalimage data is data including parallax images for right-eye display andleft-eye display. In the case where three-dimensional display modedisplay is performed, as in the case of a parallax barrier systemstereoscopic display in related art illustrated in FIG. 14, for example,a composite image including a plurality of stripe-shaped parallax imagesin one screen is produced and displayed.

The electronic paper 4 is disposed to face a side where a secondinternal reflection plane 3B is formed of the light guide plate 3. Theelectronic paper 4 is an optical device allowed to selectively switch afunction performed on an incident light ray to one of two modes, i.e., alight absorption mode and a scattering-reflection mode. The electronicpaper 4 is configured of a particle migration type display by anelectrophoresis system or an electronic liquid powder system. In theparticle migration type display, for example, positively-charged blackparticles and negatively-charged white particles are dispersed between apair of facing substrates, and the particles are moved in response to avoltage applied between the substrates to perform black display or whitedisplay. Specifically in the electrophoresis system, the particles aredispersed in a solution, and in the electronic liquid powder system, theparticles are dispersed in a gas. The above-described light absorptionmode corresponds to the case where a display surface 41 of theelectronic paper 4 is in an all-black display mode as illustrated inFIG. 1A, and the scattering-reflection mode corresponds to the casewhere the display surface 41 of the electronic paper 4 is in anall-white display mode as illustrated in FIG. 1B. In the case where animage based on three-dimensional image data is displayed on the displaysection 1 (in the case where the three-dimensional display mode isselected), the electronic paper 4 switches the function performed on anincident light ray to the light absorption mode. In the case where animage based on two-dimensional image data is displayed on the displaysection 1 (in the case where the two-dimensional mode is selected), theelectronic paper 4 switches the function performed on an incident lightray to the scattering-reflection mode.

The light source 2 is configured with use of, for example, a fluorescentlamp such as a CCFL (Cold Cathode Fluorescent Lamp), or an LED (LightEmitting Diode). One or more light sources 2 are disposed on a sidesurface of the light guide plate 3, and are allowed to applyillumination light (light rays L1) from a side surface direction of thelight guide plate 3 into an interior thereof. In FIGS. 1A and 1B, aconfiguration example in which the light sources 2 are disposed on bothside surfaces of the light guide plate 3 is illustrated.

The light guide plate 3 is configured of a transparent plastic plate of,for example, an acrylic resin. The light guide plate 3 includes a firstinternal reflection plane 3A facing the display section 1 and a secondinternal reflection plane 3B facing the electronic paper 4. The lightguide plane 3 guides light rays from the light source 2 to a sidesurface direction in a manner of total-internal-reflection between thefirst internal reflection plane 3A and the second internal reflectionplane 3B.

The entire second internal reflection plane 3B is mirror-finished, andallows light rays L1 incident at an incident angle θ1 satisfying atotal-reflection condition to be reflected in a manner oftotal-internal-reflection. The first internal reflection plane 3Aincludes scattering regions 31 and total-reflection regions 32. In thefirst internal reflection plane 3A, the total-reflection regions 32 andthe scattering regions 31 are alternately arranged in, for example, astripe pattern forming a configuration corresponding to a parallaxbarrier. In other words, as will be described later, in thethree-dimensional display mode, the light guide plate 3 is configured tofunction as a parallax barrier with the scattering region 31 as anopening section (slit section) and the total-reflection region 32 as ashielding section.

The total-reflection region 32 reflects the light rays L1 incident atthe incident angle θ1 satisfying the total-reflection condition in amanner of total-internal-reflection (reflects the light rays L1 incidentat the incident angle θ1 larger than a predetermined critical angle α ina manner of total-internal-reflection). The scattering region 31 allowssome or all of light rays incident at an angle corresponding to theincident angle 81 satisfying a predetermined total-reflection conditionin the total-reflection region 32 in incident light rays L2 to exit(allows some or all of light rays incident at an angle corresponding tothe incident angle θ1 larger than the predetermined critical angle α toexit). Moreover, in the scattering region 31, some other light rays L3in the incident light rays L2 are internally reflected.

It is to be noted that the critical angle α is represented as follow,where the refractive index of the light guide plate 3 is n1, and therefractive index of a medium (an air layer) outside the light guideplate 3 is n0 (<n1). The angles α and θ1 are angles with respect to anormal to a surface of the light guide plate. The incident angle θ1satisfying the total-reflection condition is θ1>α.sin α=n0/n1[Specific Configuration Example of Scattering Region 31]

FIG. 2A illustrates a first configuration example of a surface of thelight guide plate 3. FIG. 2B schematically illustrates reflection andscattering states of light rays on the surface of the light guide plate3 illustrated in FIG. 2A. In the first configuration example, thescattering region 31 is a recessed scattering region 31A with respect tothe total-reflection region 32. Such a recessed scattering region 31A isallowed to be formed, for example, by performing mirror-finishing on thesurface of the light guide plate 3, and then performing laser processingon a part corresponding to the scattering region 31A. In the case ofsuch a recessed scattering region 31A, some or all of light raysincident at an angle corresponding to the incident angle θ1 satisfyingthe predetermined total-reflection condition in the total-reflectionregion 32 in incident light rays do not satisfy the total-reflectioncondition in a recessed side surface section 33, and the light raysexit.

FIG. 3A illustrates a second configuration example of the surface of thelight guide plate 3. FIG. 3B schematically illustrates reflection andscattering states of light rays on the surface of the light guide plate3 illustrated in FIG. 3A. In the second configuration example, thescattering region 31 is a projected scattering region 31B with respectto the total-reflection region 32. Such a projected scattering region31B is allowed to be formed, for example, by molding the surface of thelight guide plate 3 by a die. In this case, a part corresponding to thetotal-reflection region 32 is mirror-finished by a surface of the die.In the case of such a projected scattering region 31B, some or all oflight rays incident at an angle corresponding to the incident angle θ1satisfying the predetermined total-reflection condition in thetotal-reflection region 32 in incident light rays do not satisfy thetotal-reflection condition in a projected side surface section 34, andthe light rays exit.

FIG. 4A illustrates a third configuration example of the surface of thelight guide plate 3. FIG. 4B schematically illustrates reflection andscattering states of light rays on the surface of the light guide plate3 illustrated in FIG. 4A. In the configuration examples in FIGS. 2A and3A, the surface of the light guide plate 3 is processed into a geometrydifferent from that of the total-reflection region 32 to form thescattering region 31. On the other hand, in a scattering region 31C inthe configuration example in FIG. 4A, instead of processing the surfaceof the light guide plate 3, a light-scattering member 35 is disposed ona surface, corresponding to the first internal reflection plane 3A, ofthe light guide plate 3. As the light-scattering member 35, a memberhaving a refractive index higher than the refractive index of the lightguide plate 3, for example, a PET resin with a refractive index ofapproximately 1.57 is allowed to be used. For example, a scatteringsheet formed of the PET resin is bonded to the surface of the lightguide plate 3 with use of an acrylic adhesive to form the scatteringregion 31C. In the case of the scattering region 31C in which such alight-scattering member 35 is disposed, as the refractive index ischanged by the light-scattering member 35, some or all of light raysincident at an angle corresponding to the incident angle θ1 satisfyingthe predetermined total-reflection condition in the total-reflectionregion 32 in incident light rays do not satisfy the total-reflectioncondition, and the light rays exit.

The configuration of the scattering region 31 is not limited to theabove-described configuration examples, and other configuration examplesare considered. For example, the scattering region 31 is allowed to beformed by a method such as subjecting a part corresponding to thescattering region 31 of the surface of the light guide plate 3 tosandblast processing, painting, or the like.

[Operation of Stereoscopic Display]

In the case where the stereoscopic display performs three-dimensionaldisplay mode display (refer to FIG. 1A), the display section 1 displaysan image based on the three-dimensional image data, and controls andisplay surface 41 of the electronic paper 4 to be in the all-blackdisplay mode (the light absorption mode). In this state, light rays fromthe light source 2 are reflected repeatedly in a manner oftotal-internal-reflection between the total-reflection region 32 of thefirst internal reflection plane 3A and the second internal reflectionplane 3B in the light guide plate 3 to be guided from a side surfacewhere the light source 2 is disposed to the other side surface facingthe side surface and emitted from the other side surface. On the otherhand, some light rays out of the total-reflection condition in the lightrays L2 having entered the scattering region 31 of the first internalreflection plane 3A in the light guide plate 3 exit from the scatteringregion 31. In the scattering region 31, some other light rays L3 arealso internally reflected, but the light rays L3 enter the displaysurface 41 of the electronic paper 4 through the second internalreflection plane 3B of the light guide plate 3. In this case, thedisplay surface 41 of the electronic paper 4 is in the all-black displaymode; therefore, the light rays L3 are absorbed by the display surface41. As a result, light rays exit only from the scattering region 31 ofthe first internal reflection plane 3A in the light guide plate 3. Inother words, the light guide plate 3 is allowed to equivalently functionas a parallax barrier with the scattering region 31 as an openingsection (slit section) and the total-reflection region 32 as a shieldingsection. Therefore, three-dimensional display by a parallax barriersystem in which the parallax barrier is equivalently disposed on a backsurface of the display section 1 is performed.

On the other hand, in the case where two-dimensional display modedisplay is performed (refer to FIG. 1B), the display section 1 displaysan image based on the two-dimensional image data, and controls thedisplay surface 41 of the electronic paper 4 to be in the all-whitedisplay mode (the scattering-reflection mode). In this state, light raysfrom the light source 2 are reflected repeatedly in a manner oftotal-internal-reflection between the total-reflection region 32 of thefirst internal reflection plane 3A and the second internal reflectionplane 3B in the light guide plate 3 to be guided from a side surfacewhere the light source 2 is disposed to the other side surface facingthe side surface and emitted from the other side surface. On the otherhand, in the light guide plate 3, some light rays out of thetotal-reflection condition in the light rays L2 having entered thescattering region 31 of the first internal reflection plane 3A exit fromthe scattering region 31. In the scattering region 31, some other lightrays L3 are also internally reflected, but the light rays L3 enter thedisplay surface 41 of the electronic paper 4 through the second internalreflection plane 3B of the light guide plate 3. In this case, thedisplay surface 41 of the electronic paper 4 is in the all-white displaymode; therefore, the light rays L3 are scattered and reflected by thedisplay surface 41. The light rays scattered and reflected by thedisplay surface 41 enter the light guide plate 3 through the secondinternal reflection plane 3B again, and the incident angle of the lightrays is out of the total-reflection condition in the total-reflectionregion 32, and the light rays exit from not only the scattering region31 but also the total-reflection region 32. As a result, light rays exitfrom the entire first internal reflection plane 3A in the light guideplate 3. In other words, the light guide plate 3 functions as a planarlight source similar to a typical backlight. Therefore, two-dimensionaldisplay by a backlight system in which a typical backlight isequivalently disposed on a back surface of the display section 1 isperformed.

FIG. 5 illustrates an example of luminance distributions on the surfaceof the display section 1 during three-dimensional display andtwo-dimensional display in the stereoscopic display illustrated inFIG. 1. Three-dimensional display corresponds to a state where black isdisplayed on the electronic paper 4, and two-dimensional displaycorresponds to a state where white is displayed on the electronic paper4. It is to be noted that a uniform image is displayed on the entiresurface of the display section 1. In FIG. 5, a horizontal axis indicatesa position (mm) in a horizontal direction on a screen of the displaysection 1, and a vertical axis indicates a standardized luminance value(arbitrary unit (a.u.)). It is obvious from FIG. 5 that in a state wherewhite is displayed on the electronic paper 4, uniform luminance isobtained on the entire screen. In a state where black is displayed onthe electronic paper 4, luminance varies with position, and a luminancedistribution equivalent to that in the case where a parallax barrier isarranged is obtained.

As described above, in the stereoscopic display using the light sourcedevice according to the embodiment, as the first internal reflectionplane 3A of the light guide plate 3 includes the total-reflection region32 and the scattering region 31, the light guide plate 3 is allowed toequivalently function as a parallax barrier. Therefore, compared to theparallax barrier system stereoscopic display in related art, the numberof components is allowed to be reduced, and space saving is achievable.Moreover, switching between the two-dimensional display mode and thethree-dimensional display mode is allowed to be easily performed only byswitching the display mode of the electronic paper 4.

(Second Embodiment)

Next, a stereoscopic display according to a second embodiment of thetechnology will be described below. It is to be noted that likecomponents are denoted by like numerals as of the stereoscopic displayaccording to the first embodiment, and will not be further described.

FIGS. 6A and 6B illustrate a configuration example of the stereoscopicdisplay according to the second embodiment of the technology. As in thecase of the stereoscopic display in FIGS. 1A and 1B, the stereoscopicdisplay is allowed to selectively perform switching between thetwo-dimensional display mode and the three-dimensional display mode asnecessary. FIGS. 6A and 6B correspond to a configuration in thethree-dimensional display mode, and a configuration in thetwo-dimensional display mode, respectively. FIGS. 6A and 6B alsoschematically illustrate states of emission of light rays from the lightsource device in respective display modes.

The stereoscopic display includes a polymer diffuser plate 5 instead ofthe electronic paper 4 in the stereoscopic display in FIGS. 1A and 1B.Other configurations are the same as those in the stereoscopic displayin FIGS. 1A and 1B. The polymer diffuser plate 5 is configured with useof a polymer-dispersed liquid crystal. The polymer diffuser plate 5 isdisposed to face a surface corresponding to the first internalreflection plane 3A of the light guide plate 3. The polymer diffuserplate 5 is an optical device allowed to selectively switch a functionperformed on an incident light ray to one of two modes, i.e., atransparent transmission mode and a diffuse transmission mode.

In the case where the stereoscopic display performs three-dimensionaldisplay mode display (refer to FIG. 6A), the display section 1 displaysan image based on the three-dimensional image data, and controls anentire surface of the polymer diffuser plate 5 to be in the transparenttransmission mode. In this state, light rays from the light source 2 arereflected repeatedly in a manner of total-internal-reflection betweenthe total-reflection region 32 of the first internal reflection plane 3Aand the second internal reflection plane 3B in the light guide plate 3to be guided from a side surface where the light source 2 is disposed tothe other side surface facing the side surface and emitted from theother side surface. On the other hand, some light rays out of thetotal-reflection condition in the light rays L2 having entered thescattering region 31 of the first internal reflection plane 3A in thelight guide plate 5 exit from the scattering region 31. The light rayshaving exited through the scattering region 31 enter the polymerdiffuser plate 5; however, the entire surface of the polymer diffuserplate 5 is in the transparent transmission mode; therefore, while theemission angle of the light rays from the scattering region 31 ismaintained, the light rays enter the display section 1 through thepolymer diffuser plate 5. In the scattering region 31, some other lightrays L3 are also internally reflected, but the light rays L3 exitthrough the second internal reflection plane 3B of the light guide plate3, and do not contribute to display of an image. As a result, light raysexit only from the scattering region 31 of the first internal reflectionplane 3A in the light guide plate 3. In other words, the surface of thelight guide plate 3 is allowed to equivalently function as a parallaxbarrier with the scattering region 31 as an opening section (slitsection) and the total-reflection region 32 as a shielding section.Therefore, three-dimensional display by a parallax barrier system inwhich the parallax barrier is equivalently disposed on a back surface ofthe display section 1 is performed.

On the other hand, in the case where two-dimensional display modedisplay is performed (refer to FIG. 6B), the display section 1 displaysan image based on the two-dimensional image data, and controls theentire surface of the polymer diffuser plate 5 to be in the diffusetransmission mode. In this state, light rays from the light source 2 arereflected repeatedly in a manner of total-internal-reflection betweenthe total-reflection region 32 of the first internal reflection plane 3Aand the second internal reflection plane 3B in the light guide plate 3to be guided from a side surface where the light source 2 is disposed tothe other side surface facing the side surface and emitted from theother side surface. On the other hand, in the light guide plate 3, somelight rays out of the total-reflection condition in the light rays L2having entered the scattering region 31 of the first internal reflectionplane 3A exit from the scattering region 31. In this case, light rayshaving exited through the scattering region 31 enter the polymerdiffuser plate 5; however, the entire surface of the polymer diffuserplate 5 is in the diffuse transmission mode; therefore, light raysentering the display section 1 are diffused by the entire surface of thepolymer diffuser plate 5. As a result, the whole light source devicefunctions as a planar light source similar to a typical backlight.Therefore, two-dimensional display by a backlight system in which atypical backlight is equivalently disposed on a back surface of thedisplay section 1 is performed.

(Third Embodiment)

Next, a stereoscopic display according to a third embodiment of thetechnology will be described below. It is to be noted that likecomponents are denoted by like numerals as of the stereoscopic displayaccording to the first or second embodiment, and will not be furtherdescribed.

FIGS. 7A and 7B illustrate a configuration example of the stereoscopicdisplay according to the third embodiment. As in the case of thestereoscopic display illustrated in FIGS. 1A and 1B, the stereoscopicdisplay is allowed to selectively perform switching between thetwo-dimensional display mode and the three-dimensional display mode asnecessary. FIGS. 7A and 7B correspond to a configuration in thethree-dimensional display mode, and a configuration in thetwo-dimensional display mode, respectively. FIGS. 7A and 7B alsoschematically illustrate states of emission of light rays from the lightsource device in respective display modes.

In the stereoscopic display, the light source device includes abacklight 7 configured of a planar light source, instead of theelectronic paper 4 in the stereoscopic display in FIGS. 1A and 1B. Otherconfigurations are the same as those in the stereoscopic display inFIGS. 1A and 1B. The backlight 7 is another light source different fromthe light source 2 disposed on the side surface of the light guide plate3, and is disposed to face a surface corresponding to the secondinternal reflection plane 3B of the light guide plate 3. The backlight 7externally emits illumination light to the second internal reflectionplane 3B. ON (light-on)/OFF (light-off) control of the backlight 7 isperformed in response to switching between the two-dimensional displaymode and the three-dimensional display mode.

In the case where the stereoscopic display performs three-dimensionaldisplay mode display (refer to FIG. 7A), the display section 1 displaysan image based on the three-dimensional image data, and controls anentire surface of the backlight 7 to stay in an OFF (light-off) state.The light source 2 disposed on the side surface of the light guide plate3 is controlled to stay in an ON (light-on) state. In this state, lightrays from the light source 2 are reflected repeatedly in a manner oftotal-internal-reflection between the total-reflection region 32 of thefirst internal reflection plane 3A and the second internal reflectionplane 3B in the light guide plate 3 to be guided from a side surfacewhere the light source 2 is disposed to the other side surface facingthe side surface and emitted from the other side surface. On the otherhand, some light rays out of the total-reflection condition in the lightrays L2 having entered the scattering region 31 of the first internalreflection plane 3A in the light guide plate 3 exit from the scatteringregion 31. In the scattering region 31, some other light rays areinternally reflected, but the light rays exit through the secondinternal reflection plane 3B of the light guide plate 3, and do notcontribute to display of an image. As a result, in the light guide plate3, light rays exit only from the scattering region 31 of the firstinternal reflection plane 3A. In other words, the surface of the lightguide plate 3 is allowed to equivalently function as a parallax barrierwith the scattering region 31 as an opening section (slit section) andthe total-reflection region 32 as a shielding section. Therefore,three-dimensional display by a parallax barrier system in which theparallax barrier is equivalently disposed on a back surface of thedisplay section 1 is performed.

On the other hand, in the case where two-dimensional display modedisplay is performed (refer to FIG. 7B), the display section 1 displaysan image based on the two-dimensional image data, and controls theentire surface of the backlight 7 to be in the ON (light-on) state. Thelight source 2 disposed on the side surface of the light guide plate 3is controlled to be, for example, in the light off state. In this state,light rays from the backlight 7 enter the light guide plate 3 throughthe second internal reflection plane 3B at an angle substantiallyperpendicular to the light guide plate 3. Therefore, the incident angleof the light rays is out of the total-reflection condition in thetotal-reflection region 32, and the light rays exit from not only thescattering region 31 but also the total-reflection region 32. As aresult, the light rays exit from the entire first internal reflectionplane 3A of the light guide plate 3. In other words, the light guideplate 3 functions as a planar light source similar to a typicalbacklight. Therefore, two-dimensional display by a backlight system inwhich a typical backlight is equivalently disposed on a back surface ofthe display section 1 is performed.

It is to be noted that in the case where two-dimensional display modedisplay is performed, the light source 2 disposed on the side surface ofthe light guide plate 3 may be controlled to stay in the ON (light-on)state with the backlight 7. Moreover, in the case where thetwo-dimensional display mode display is performed, the light source 2may perform switching between the light-off state and the light-on stateas necessary. Therefore, for example, in the case where there is adifference in luminance distribution between the scattering region 31and the total-reflection region 32 when only the backlight 7 is turnedon, the luminance distribution on the entire surface is allowed to beoptimized by appropriately adjusting the light state of the light source2 (performing ON/OFF control or adjusting a light amount).

(Fourth Embodiment)

Next, a stereoscopic display according to a fourth embodiment of thetechnology will be described below. It is to be noted that likecomponents are denoted by like numerals as of the stereoscopic displaysaccording to the first to third embodiments, and will not be furtherdescribed.

[Whole Configuration of Stereoscopic Display]

In the above-described first to third embodiments, the configurationexample in which in the light guide plate 3, the scattering region 31and the total-reflection region 32 are provided in the first internalreflection plane 3A is described; however, they may be provided in thesecond internal reflection plane 3B. For example, in the configurationin the above-described third embodiment (refer to FIGS. 7A and 7B), thescattering region 31 and the total-reflection region 32 may be providedin the second internal reflection plane 3B.

FIGS. 8 to 10 illustrate configuration examples of a stereoscopicdisplay with such a configuration. The stereoscopic display is allowedto selectively perform switching between the two-dimensional displaymode and the three-dimensional display mode as necessary by control ofthe light source similar to that in the stereoscopic display in FIG. 7.FIG. 8 schematically illustrates a state of light rays exiting from thelight source device in the case where only the light source 2 is in theON (light-on) state, and corresponds to the three-dimensional displaymode. FIG. 9 schematically illustrates a state of light rays exitingfrom the light source device in the case where only the backlight 7 isin the ON (light-on) state, and corresponds to the two-dimensionaldisplay mode. Moreover, FIG. 10 schematically illustrates a state oflight rays exiting from the light source device in the case where bothof the light source 2 and the backlight 7 are in ON (light-on) state,and also corresponds to the two-dimensional display mode.

In the embodiment, the entire first internal reflection plane 3A of thelight guide plate 3 is mirror-finished, and allows light rays incidentat an incident angle satisfying the total-reflection condition to bereflected, in a manner of total-internal-reflection, in the interior ofthe light guide plate 3, and allows light rays out of thetotal-reflection condition to exit therefrom.

The second internal reflection plane 3B has the scattering region 31 andthe total-reflection region 32. As will be described later, thescattering region 31 is formed by laser processing, sandblast processingor coating on a surface of the light guide plate 3 or bonding asheet-like light-scattering member on the surface of the light guideplate 3. In the second internal reflection plane 3B, in thethree-dimensional display mode, the scattering region 31 and thetotal-reflection region 32 function as an opening section (a slitsection) and a shielding section of a parallax barrier for firstillumination light (light rays L1) from the light source 2,respectively. In the second internal reflection plane 3B, the scatteringregion 31 and the total-reflection region 32 are arranged in a patternforming a configuration corresponding to a parallax barrier. In otherwords, the total-reflection region 32 is arranged in a patterncorresponding to a shielding section in the parallax barrier, and thescattering region 31 is arranged in a pattern corresponding to anopening section in the parallax barrier. It is to be noted that as abarrier pattern of the parallax barrier, for example, a stripe patternin which a large number of vertically long slit-like opening sectionsare arranged in parallel with shielding sections in between is known.However, as the barrier pattern, any of various known barrier patternsin related art may be used, and the barrier pattern is not specificallylimited.

The first internal reflection plane 3A and the total-reflection region32 of the second internal reflection plane 3B reflect light raysincident at the incident angle θ1 satisfying the total-reflectioncondition in a manner of total-internal-reflection (reflect light raysincident at the incident angle θ1 larger than a predetermined criticalangle α in a manner of total-internal-reflection). Therefore, the firstillumination light incident from the light source 2 at the incidentangle θ1 satisfying the total-reflection condition is guided to a sidesurface direction in a manner of total-internal-reflection between thefirst internal reflection plane 3A and the total-reflection region 32 ofthe second internal reflection plane 3B. Moreover, as illustrated inFIG. 9 or FIG. 10, the total-reflection region 32 allows secondillumination light from the backlight 7 to pass therethrough to emit thesecond illumination light as a light ray out of the total-reflectioncondition toward the first internal reflection plane 3A.

As illustrated in FIG. 8, the scattering region 31 scatters and reflectsthe first illumination light (light rays L1) from the light source 2,and emits a part or all (scattered light L20) of the first illuminationlight L1 toward the first internal reflection plane 3A as light rays outof the total-reflection condition.

[Specific Configuration Example of Scattering Region 31]

FIG. 11A illustrates a first configuration example of the secondinternal reflection plane 3B in the light guide plate 3. FIG. 11Bschematically illustrates reflection and scattering states of light rayson the second internal reflection plane 3B in the first configurationexample illustrated in FIG. 11A. In the first configuration example, thescattering region 31 is a recessed scattering region 31A with respect tothe total-reflection region 32. Such a recessed scattering region 31A isallowed to be formed by, for example, sandblast processing or laserprocessing. For example, a surface of the light guide plate 3 ismirror-finished, and then a part corresponding to the scattering region31A is subjected to laser processing to form the scattering region 31A.In the first configuration example, first illumination light L11incident from the light source 2 at the incident angle θ1 satisfying thetotal-reflection condition is reflected in a manner oftotal-internal-reflection by the total-reflection region 32 of thesecond internal reflection plane 3B. On the other hand, even if lightenters the recessed scattering region 31A at the same incident angle θ1as in the case where light enters the total-reflection region 32, somelight rays of first illumination light L12 having entered the recessedscattering region 31A do not satisfy the total-reflection condition on aside surface portion 33 of a recessed shape, and are scattered and passthrough the side surface portion 33, and other light rays are scatteredand reflected. As illustrated in FIG. 8, some or all of light rays(scattered light L20) scattered and reflected are emitted as light raysout of the total-reflection condition toward the first internalreflection plane 3A.

FIG. 12A illustrates a second configuration example of the secondinternal reflection plane 3B of the light guide plate 3. FIG. 12Bschematically illustrates reflection and scattering states of light rayson the second internal reflection plane 3B in the second configurationexample illustrated in FIG. 12A. In the second configuration example,the scattering region 31 is a projected scattering region 31B withrespect to the total-reflection region 32. Such a projected scatteringregion 31B is allowed to be formed, for example, by molding a surface ofthe light guide plate 3 by a die. In this case, a part corresponding tothe total-reflection region 32 is mirror-finished by a surface of thedie. In the second configuration example, the first illumination lightL11 incident from the light source 2 at the incident angle θ1 satisfyingthe total-reflection condition is reflected in a manner oftotal-internal-reflection by the total-reflection region 32 of thesecond internal reflection plane 3B. On the other hand, even if lightenters the projected scattering region 31B at the same incident angle θ1as in the case where light enters the total-reflection region 32, somelight rays of first illumination light L12 having entered the projectedscattering region 31B do not satisfy the total-reflection condition on aside surface portion 34 of a projected shape, and are scattered and passthrough the side surface portion 34, and other light rays are scatteredand reflected. As illustrated in FIG. 8, some or all of light rays(scattered light L20) scattered and reflected are emitted as light raysout of the total-reflection condition toward the first internalreflection plane 3A.

FIG. 13A illustrates a third configuration example of the secondinternal reflection plane 3B of the light guide plate 3. FIG. 13Bschematically illustrates the reflection and scattering states of lightrays on the second internal reflection plane 3B in the thirdconfiguration example illustrated in FIG. 13A. In the configurationexamples in FIGS. 11A and 12A, the surface of the light guide plate 3 isprocessed into a geometry different from that of the total-reflectionregion 32 to form the scattering region 31. On the other hand, in ascattering region 31C in the configuration example in FIG. 13A, insteadof processing the surface of the light guide plate 3, a light-scatteringmember 35 made of a material different from that of the light guideplate 3 is disposed on a surface, corresponding to the second internalreflection plane 3B, of the light guide plate 3. In this case, a whitepaint (for example, barium sulfate) as the light-scattering member 35 ispatterned on the surface of the light guide plate 3 by screen printingto form the scattering region 31C. In the third configuration example,the first illumination light L11 incident from the light source 2 at theincident angle θ1 satisfying the total-reflection condition is reflectedby the total-reflection region 32 of the second internal reflectionplane 3B in a manner of total-internal-reflection. On the other hand,even if light enters the scattering region 31C where thelight-scattering member 35 is disposed at the same incident angle θ1 asin the case where light enters the total-reflection region 32, a part ofthe first illumination light L12 having entered the scattering region31C is scattered and passes through the scattering region 31C by thelight-scattering member 35, and the other is scattered and reflected.Some or all of light rays scattered and reflected are emitted as lightrays out of the total-reflection condition toward the first internalreflection plane 3A.

[Operation of Stereoscopic Display]

In the case where the stereoscopic display performs three-dimensionaldisplay mode display, the display section 1 displays an image based onthe three-dimensional image data, and ON (light-on)/OFF (light-off)control of the light source 2 and the backlight 7 is performed forthree-dimensional display. More specifically, as illustrated in FIG. 8,the light source 2 is controlled to stay in an ON (light-on) state, andthe backlight 7 is controlled to stay in an OFF (light-off) state. Inthis state, first illumination light (light rays L1) from the lightsource 2 is reflected repeatedly in a manner oftotal-internal-reflection between the first internal reflection plane 3Aand the total-reflection region 32 of the second internal reflectionplane 3B in the light guide plate 3 to be guided from a side surfacewhere the light source 2 is disposed to the other side surface facingthe side surface and emitted from the other side surface. On the otherhand, a part of the first illumination light from the light source 2 isscattered and reflected by the scattering region 31 of the light guideplate 3 to pass through the first internal reflection plane 3A of thelight guide plate 3 and exit from the light guide plate 3. Therefore,the light guide plate 3 is allowed to have a function as a parallaxbarrier. In other words, for the first illumination light from the lightsource 2, the light guide plate 3 is allowed to equivalently function asa parallax barrier with the scattering region 31 as an opening section(slit section) and the total-reflection region 32 as a shieldingsection. Therefore, three-dimensional display by a parallax barriersystem in which the parallax barrier is equivalently disposed on a backsurface of the display section 1 is performed.

On the other hand, in the case where two-dimensional display modedisplay is performed, the display section 1 displays an image based onthe two-dimensional image data, and ON (light-on)/OFF (light-off)control of the light source 2 and the backlight 7 is performed fortwo-dimensional display. More specifically, for example, as illustratedin FIG. 9, the light source 2 is controlled to stay in an OFF(light-off) state, and the backlight 7 is controlled to stay in an ON(light-on) state. In this case, second illumination light from thebacklight 7 passes through the total-reflection region 32 of the secondinternal reflection plane 3B to exit as a light ray out of thetotal-reflection condition from substantially the entire first internalreflection plane 3A. In other words, the light guide plate 3 functionsas a planar light source similar to a typical backlight. Therefore,two-dimensional display by a backlight system in which a typicalbacklight is equivalently disposed on a back surface of the displaysection 1 is performed.

It is to be noted that when only the backlight 7 is turned on, thesecond illumination light exits from substantially the entire surface ofthe light guide plate 3, and if necessary, the light source 2 may beturned on as illustrated in FIG. 10. Therefore, for example, in the casewhere there is a difference in luminance distribution between partscorresponding to the scattering region 31 and the total-reflectionregion 32 when only the backlight 7 is turned on, the luminancedistribution on an entire surface is allowed to be optimized byappropriately adjusting the light state of the light source 2(performing ON/OFF control or adjusting a light amount). However, forexample, in the case where luminance is sufficiently corrected in thedisplay section 1 in two-dimensional display, only the backlight 7 maybe turned on.

As described above, in the stereoscopic display using the light sourcedevice according to the embodiment, the scattering region 31 and thetotal-reflection region 32 are provided in the second internalreflection plane 3B of the light guide plate 3, and the firstillumination light from the light source 2 and the second illuminationlight from the backlight 7 are allowed to selectively exit from thelight guide plate 3; therefore, the light guide plate 3 is allowed toequivalently function as a parallax barrier.

(Other Embodiments)

The present technology is not limited to the above-describedembodiments, and may be variously modified. For example, in theabove-described embodiments, configuration examples in which in thelight guide plate 3, the scattering region 31 and the total-reflectionregion 32 are provided in one of the first internal reflection plane 3Aand the second internal reflection plane 3B are described; however, thescattering region 31 and the total-reflection region 32 may be providedin both of the first internal reflection plane 3A and the secondinternal reflection plane 3B.

Moreover, in the above-described embodiments, the case where switchingbetween three-dimensional display and two-dimensional display isselectively performed on an entire screen is described; however,selective switching between three-dimensional display andtwo-dimensional display may be controlled for each of partial regionsthereof. In other words, three-dimensional display may be performed onone region in one screen, and two-dimensional display may be performedon another region. In three-dimensional display, resolution declines,compared to the case of two-dimensional display; therefore, in somecases, two-dimensional display is preferable in visibility of an image.For example, in the case where a film with subtitles isthree-dimensionally displayed, the subtitles are easily viewed byperforming two-dimensional display on only a region where subtitles areto be displayed. Moreover, it is considered that in a portable terminaldevice such as a cellular phone, while two-dimensional display isperformed on only a region where an icon or the like indicating signalstrength or a battery level is displayed, three-dimensional display isperformed on another region.

To control such switching, for each of partial regions, betweenthree-dimensional display and two-dimensional display, in the displaysection 1, each of partial regions selectively displays one of athree-dimensional image based on three-dimensional image data and atwo-dimensional image based on two-dimensional image data. Moreover, anoptical device allowed to control, for each of partial region thereof,the state of light rays exiting therefrom is used.

More specifically, in the case where the electronic paper 4 is used asthe optical device as in the case of the configuration example in FIGS.1A and 1B, the electronic paper 4 is controlled to switch, for each ofpartial regions thereof, a function performed on an incident light rayin a part corresponding to a region where three-dimensional display isperformed in the display section 1 to a light absorption mode (a blackdisplay mode), and to switch a function performed on an incident lightray in a part corresponding to a region where two-dimensional display isperformed in the display section 1 to a scattering-reflection mode (awhite display mode). Moreover, in the case where the polymer diffuserplate 5 is used as the optical device as in the case of theconfiguration example illustrated in FIGS. 6A and 6B, the polymerdiffuser plate 5 is controlled to switch, for each of partial regionthereof, a function performed on an incident light ray in a partcorresponding to a region where three-dimensional display is performedin the display section 1 to a transparent transmission mode, and toswitch a function performed on an incident light ray in a partcorresponding to a region where two-dimensional display is performed inthe display section 1 to a diffuse transmission mode. Further, in thecase where the backlight 7 is used as the optical device as in the caseof the configuration example illustrated in FIGS. 7A and 7B or FIGS. 8to 10, as the backlight 7, a backlight allowed to control lighting foreach of partial regions is used. Then, in the display section 1, in thebacklight 7, a part corresponding to a region where three-dimensionaldisplay is performed is controlled to be a light-off (OFF) state, and apart corresponding to a region where two-dimensional display isperformed in the display section 1 is controlled to stay in a light-on(ON) state.

The present application contains subject matter related to thatdisclosed in Japanese Priority Patent Application 2011-15569 filed inthe Japan Patent Office on Jan. 27, 2011, the entire content of which ishereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations, and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A display device comprising a display section anda light source device, the light source device including: a light guideplate having a first plane and a second plane which face each other; oneor more light sources each disposed beside the light guide plate along aside surface thereof; and an optical device disposed to face the secondplane, wherein the display section is disposed to face the first plane,one or both of the first plane and the second plane of the light guideplate each have regions each allowing a part of light from the lightsources to exit from the light guide plate, and at least a part of theoptical device corresponding to a region of the display sectionperforming a three-dimensional display is controlled to stay in alight-off state.
 2. The display device according to claim 1, whereinother part of the optical device corresponding to a region of thedisplay section performing a two-dimensional display is controlled tostay in a light-on state.
 3. The display device according to claim 1,wherein one or both of the first plane and the second plane of the lightguide plate each have reflecting regions and the scattering regions. 4.The display device according to claim 3, wherein reflecting regions andthe scattering regions are alternately arranged in one or both of thefirst and second internal reflection planes.
 5. The display deviceaccording to claim 3, wherein the scattering region is formed byprocessing a surface of the light guide plate into a geometry differentfrom that of the reflecting region, the surface corresponding to thefirst internal reflection plane or the second internal reflection plane.6. The display device according to claim 3, wherein the scatteringregion is formed by disposing, on a surface of the light guide plate, alight-scattering member with a refractive index higher than that of thelight guide plate, the surface corresponding to the first internalreflection plane or the second internal reflection plane.
 7. A displaydevice comprising a display section and a light source device, the lightsource device including: a light guide plate having a first plane and asecond plane which face each other; one or more light sources eachdisposed beside the light guide plate along a side surface thereof; andan optical device disposed to face the second plane, wherein the displaysection is disposed to face the first plane, one or both of the firstplane and the second plane of the light guide plate each have regionseach allowing a part of light from the light sources to exit from thelight guide plate, and at least a part of the optical devicecorresponding to a region of the display section displaying parallaximages is controlled to stay in a light-off state.
 8. The display deviceaccording to claim 7, wherein one or both of the first plane and thesecond plane of the light guide plate each have reflecting regions andthe scattering regions.
 9. The display device according to claim 8,wherein reflecting regions and the scattering regions are alternatelyarranged in one or both of the first and second internal reflectionplanes.
 10. The display device according to claim 8, wherein thescattering region is formed by processing a surface of the light guideplate into a geometry different from that of the reflecting region, thesurface corresponding to the first internal reflection plane or thesecond internal reflection plane.
 11. The display device according toclaim 8, wherein the scattering region is formed by disposing, on asurface of the light guide plate, a light-scattering member with arefractive index higher than that of the light guide plate, the surfacecorresponding to the first internal reflection plane or the secondinternal reflection plane.
 12. A display device comprising: a displaypanel configured to display a plurality of parallax images; a lightguide plate having a first plane and a second plane which face eachother; and one or more light sources each disposed beside the lightguide plate along a side surface thereof, wherein the display section isdisposed to face the first plane, one or both of the first plane and thesecond plane of the light guide plate each have regions each allowing apart of light from the light sources to exit from the light guide plate,at least one of the first plane and the second plane of the light guideplate has a plurality of regions configured to exit a part of light fromthe light guide plate within 1 millimeter cycle corresponding to theparallax images.